Is 48 too old to have a baby?

[brk10]

I'm 48 and met the love of my life a few years ago.  I've been thinking about having a baby constantly in the recent year.  I'm healthy.  My FSH level is 5.0.  I have a fairly normal cycle.  I have not ever been pregnant before.  We are not interested in IVF or other medical interventions and we are not interested in adoption.
I know there are tremendous risks at my age for self and baby.  I know that our risk is high of having a chromosomal abnormality as well as other abnormalities.  Also, my husband (age 52) did find out, in his late 30's, that he apparently had spina bifida.  It has had no effects on him, as they never originally detected it.  And also 2 of his cousins's children are autistic.
We have a great life and were very fortunate to have found each other, but I can't help but wonder about the possibility of a child.
I'm prevailing upon you ladies who have similar feelings or feel like telling me straight up that I should leave well enough alone.
Even if I were to get pregnant without any intervention, which I know is rare, -- life will be drastically different.  
Are there any older new (or again) mom's out there that could be honest with me?
I'm wondering (out loud) if it's too risky for us to try once or twice (unprotected sex) to "close this chapter"?